biologe

Blog and online journal with editorial content about science, art and nature.

Tag: September

Drone flights: Worth seeing nature around the fields of Berlin

The metropolis Berlin is the capital of Germany and much more than that. It represents an unusual green city. When using elevated viewpoints to watch the cityshape, then at least in summer visitors of Berlin can receive the impression of being in the midst of a greening huge landscapes with several villages in between.

 

Green areas in Berlin

 

 

Indeed related to other metropolitan cities of the world, Berlin is still partly not very densely populated and covered by remarkable huge natural countryside instead. The area of landing and runway strips of the former airport Tempelhof for example up to date represents the largest coherent green area inside a city worldwide. The so called Tempelhofer Feld was after the termination of the air traffic exposed to renaturation and is currently a very popular recreational park. It’s located in the South of the city.

Also the West and South-West partly represent nature reserve areas and are covered by the big urban forest Grunewald.

 

Meadows and wetlands in the North of Berlin as nature refuges

 

I am since two years discovering the Northern parts of Berlin, which according to my random observations (in comparison with other Berlin areas, such as Tempehofer Feld, Teufelsberg (Grunewald) and some urban parks in the center of the city; examples of species will be visible on my corresponding blog article) bears the greatest biodiversity in bloom visiting insects.

 

 

 

Mosaic of different landscape types close to each other

 

 

 

 

 

This is seemingly due to the complexity of different meadow-, field-, wetland- and bog-habitats, being originally shaped by the Weichselian-glaciers. I regularly visited the stream valley of the so called Tegeler Fließ with the lake Köppchensee. It’s a hilly area with different gradients of sunny slopes with partly Mediterranean climatic conditions, surrounded by different kinds of wetlands. This area is well known for its great biodiversity.

 

Between the villages Rosenthal, Lübars and Blankenfelde

 

But my drone flights present vast tracts in the South of that stream valley, consisting of fields, green meadows and wetlands. It is the area between the Berlin villages Rosenthal, Lübars and Blankenfelde. Inner urban agriculture is rare in metropolian cities worldwide, in Berlin there is only a small agriculture area in the South (Dahlem Dorf) and the fields between the named villages in the North.

 

Drone flights and bloom visiting insects

 

 

Fields and meadows with adjacent forests and wetlands in the North of Berlin, September 2019, copyrights Stefan F. Wirth. Please give my video also your like on Youtube.

 

Most part of the footage in my film represents the fields adjacent to the village Rosenthal. I newly discovered the partly quite tiny meadows between and adjacent to agricultural fields around Rosenthal this summer and discovered an impressive and steadily visible diversity of bloom visiting insects there. Fields as monoculture habitats usually bear a smaller biodiversity related to wild-growing nature zones. But due to the connection of the edges of fields with complex nature refuge zones around, I could observe a quite great number of species on closely adjacent meadows and even the natural border zones of these agricultural areas.

 

Videographic details

 

The footage was captured in 4K and D-cinelike quality using a Mavic 2 Zoom drone between September and October 2019.

 

 

Berlin, September/ October 2019, copyrights Stefan F. Wirth

 

Different wing colors in a harlequin ladybeetle specimen

The ladybeetle Harmonia axyridis is naturally distributed over eastern Asia, but was imported to the United States already at the beginning of the 20th century as pest control. At first, there was no population development in the open fields. These were at first reported from Louisiana in 1988. In 2001 the first free living specimens were for Europe discovered in Belgium. Since then the beetle distributed over several European countries, such as France, entire Germany or Switzerland.

 

Variations of Harmonia axyridis

 

The beetle is well known for its great form variations. Worldwide more than 200 different color pattern forms of thorax and elytrae are described. They are distinctly shaped and maintain in this shape and arrangement of pattern. But four forms dominate within natural populations. Speaking about the elytrae (not the thorax patterns), the reddish form with dark spots, as visible in my film, is one of them.

These distinct different forms must be named a polymorphism and are based on genetic information as well as on environmental conditions, such as temperature, humidity and light intensitivity. According to that even the term polyphenism might be adequate.

 

 

 

 

Transcription factor pannier responsible for color pattern polymorphism

 

According to the work of M. Gautier et al. (the genomic basis of color pattern polymorphism  in the harlequin ladybird, Current biology, 28, 20), the transcription factor pannier is responsible for the genetically based control of this polymorphism. They discovered that different pannier alleles determine the color pattern in the different known forms. The authors furthermore report that pannier was never found before to play a keyfactor role in the pigmentation of insects.

 

Ladybeetle species on a meadow in Berlin

 

The specimen in my footage was discovered on an urban meadow in the park area „Nordhafen“ in Berlin. It’s a meadow in autumn predominantly consisting of lucerne and clover, sorrel and yellow field cress. Different ladybeetle species could be in greater numbers found there between September and October 2019. The sevenspot-ladybird, the adonis ladybird (Hippodamia variegata) and most abundant the harlquin ladybird in all its developmental stages.

 

Asymmetrical wing colors and possible explications

 

 

Harlequin beetle specimen from Berlin with asymmetrically colored wings, copyrights Stefan F. Wirth, please like my video also on Youtube

 

The most conspicuous character of „my“ harlequin ladybird specimen was its distinct asymmetrically colored wings (elytrae). One side reddish with black spots, the other side brownish with black spots. During my research about such asymmetries in ladybirds, I didn’t find recent studies, which distinctly focussed on that topic. H. E. Roy et al. reported in their book „ladybirds“ (original version 1989, revised version 2013) about the existance of such differently colored wings in the same specimen. They emphasized that the phenominon was not studied in detail, but assumed different factors being eventually responsible for such a development of a beetle individual: 1) disruption of pigment production, 2) mitotic mutation in early development, 3) environmental conditions, eventually influencing the colors of an originally normal developed young adult (exposed for longer time to different light intensities etc.). The latter might in the case of „my“ specimen being an indeed possible factor, as it is clearly visible that also the brownish wing has at its edges some of the reddish pigments.

 

 

Filming/ photography conditions

 

The beetles was filmed and photographed under artificial conditions in a soil and grass-set in my video lab. There, mites of the Gamasina (Parasitiformes, evtl. mostly Laelapidae) were common. They interestingly showed a phoretic behavior by quickly climbing onto the wings of that ladybeetle. They obviously recognized it as a suitable carrier to new habitats. I assume ladybeetles in the field not being of much attraction for phoretic dispersal, based on their life-cycles and preferred habitats.

 

Berlin, September/ October 2019, Copyrights Stefan F. Wirth